CVE-2025-40078: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-40078 is a vulnerability discovered in the Linux kernel related to improper access validation in the bpfsockaddr functionality. The vulnerability was disclosed on October 28, 2025, and affects the BPF (Berkeley Packet Filter) subsystem (NVD).

The vulnerability stems from insufficient validation of accesses to bpfsockaddr in the Linux kernel. Specifically, the issue occurs when accessing offset 60 in bpfsockaddr, which corresponds to an implicit padding of 4 bytes after msgsrcip4. The access to this padding isn't properly rejected in sockaddrisvalidaccess, leading to a verifier bug during ctx access conversion. The vulnerability has been assigned a CVSS v3.1 base score of 5.5 with the vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H (Red Hat).

The vulnerability can result in a kernel warning when exploited, potentially leading to system availability issues. The CVSS metrics indicate that while there is no impact on confidentiality or integrity, there is a high impact on system availability (Red Hat).

The vulnerability has been addressed through patches that explicitly check the various fields of bpfsockaddr in sockaddrisvalidaccess. Red Hat has marked this as 'Fix deferred' for Red Hat Enterprise Linux versions 8, 9, and 10, while version 7 is not affected (Red Hat).